Photoprinting machine



Nov. 25, 1947.

P. B. STREICH PHOTOPRINTING MACHINE Filed Feb. 20, 1945' 2 Sheets-Sheet1 INVENTOR. 5. 5795/0 @04 Y 7 f ATTORJYEYS Nov. 25, 1947- I P. B.STREICH 2,431,520

PHOTOPRINTING MACHINE v F iled Feb. 20, 1945 2 Sheets-Sheet 2 QOOQ OOQooIN V EN TOR. B401- 57752709 Patented Nov. 25, 1947 UNITED STATES PATENTOFFICE PHOTOPRINTING MACHINE.

Paul B. Streich, Maywood, Ill., assignor to Charles Bruning Company,Inc., New York, N. Y., a corporation of New York Application February20, 1945, Serial No. 578,840

Claims.

This invention relates to improvements in printing machines forsensitized material, and more particularly, to printing means of thegeneral type in which sensitized material such as paper, is fed around arevolving light-transmitting or transparent cylinder containing lightingor illuminating means adapted for printing purposes, the tracings or thelike of which prints are to be made, being fed between the sensitizedmaterial and the cylinder.

In machines of this type heat radiating from the lamp tends to heat thetransparent cylinder to a high temperature and consequently, thetracings and the sensitized material. Inasmuch as heat has anaccelerating action on diazosensitized material, uneven heating, andtherefore contact temperature, along the length of the cylinder resultsin uneven effective exposure of the sensitized material. Such heatingis, therefore, distinctly undesirable, and it has been proposed to coolthe cylinder by placing a suction device at one end thereof and drawingthrough the cylinder air admitted at the other end thereof. However, theresults are unsatisfactory in that the cooling of the cylinder is notuniform. In the foregoing machines, it has also been difficult to removetracings and the like from the sensitized paper or material.

An important object of the invention is to provide novel andadvantageous means for cooling the apparatus.

A further object of the invention is to provide an improved means ofeffecting even cooling of the apparatus.

Another object is to provide for cooling the apparatus by drawing airfrom a casing enclosing the apparatus, and thereby drawing cooling airinto the casing.

A further object of the invention is to provide means for more uniformcooling of the cylinder.

Another object is to provide means for effecting internal cooling of thecylinder whereby the cooling is substantially uniform from end to end.

Still another object is to provide means for supplying air to theinterior of the cylinder intermediate its ends and withdrawing such airfrom both ends of the cylinder.

Another object of the present invention is to provide means for coolingthe cylinder substantially uniformly from end to end, comprising meansentering the cylinder longitudinally and.

supplyin air as required at different points along said cylinder, andmeans for withdrawing air from the cylinder.

A further object is to provide means for conducting air by one or moreducts, through both sides of the printer into the interior of therotating cylinder intermediate its ends, discharging the air from saidduct or ducts into the interior of the cylinder at one or moreintermediate points, and Withdrawing the heated air through both ends ofthe cylinder into the interior of the casing of the machine.

Another object is to provide one or more ducts extending into the rotarycylinder and discharg ing cooling air in directions to tend to producecurrents of air around the inner surface of the cylinder, and means todraw air from the cylinder longitudinally and cause the air to move inhelical currents.

Still another object is to utilize the cooling means for the separationof tracings from the exposed printing paper or other material.

Another object of the invention is to provide apparatus in which therotary transparent cylinder is enclosed in the casing of the machine andoutside air, supplied to the interior of the cylinder intermediate itsends through one or more ducts, is drawn from both ends of the cylinderinto the casing and, together with air entering the casing at one ormore other points, is withdrawn from the casing by the same exhaustmeans.

Another object of the present invention is to provide apparatus of thecharacter specified in which the partial vacuum-maintained in thecasing' is utilized to separate tracings and the like from thesensitized paper.

A"further object is to provide apparatus of the general type referred toin which exhaust means for the chamber draws air from the outsidethrough duct means to the interior of the revolving cylinder at anintermediate part, draws the heated air from both ends of the cylinderinto the casing, and draws air into the casing and over the cylinder tocool the cylinder, the bands and the upper part of the casing and toseparate the tracings from the exposed paper or the like.

Other objects, features, and advantages will appear upon considerationof the following detailed description and of the drawings, in whichFigure 1 is a view in transverse vertical sec-Q tion of printingapparatus embodying one feature of the invention;

Figure 2 is a section taken along the line 2-2 I of Figure 1; v

Figure 3 is a view similar to Figure 2, showing a mi dified form of theinvention;

Figure 4 is a view similar to Figure 2, showing yet another modifiedform of the invention, the view being on the section line 44 of Figure5; and

Figure 5 is a view in transverse section, taken on line 55 of Figure 4and looking in the direction of the arrows.

Referring to the drawings, the printer comprises apparatuswithin acasing I0, having a bottom H, a front wall i2, a rear wall 13, a rightside wall 14, a left side wall I5 and a top l5. Mounted transversely ofthe casing 10, andin the upper part thereof, is a rotatablelight-transmitting cylinder I! of heatresistingmaterial such as Pyrex. Asuitable. lamp l8, such, as :a mercury vapor lamp, is mounted coaxiallyof said cylinder H, the cylinder receiving tracings l8 and sensitizedpaper on the outer surface thereof. The cylinder I1 is suitably mountedfor rotation about its axis, as for example, by being suspended by aseries of endless bands 23 which also serve to hold the tracings l9 andthe sensitized paper 20 against the rotating cylinder ll. Instead of .aseries of endless bands, as above described, it is contemplated that aperforated band would be used.

Said bands 23 pass upwardly and rearwardly over a roll 24 to a roll25adjacent to the front of cylinder ll, thus providing .a travelingplatform to receive the tracings and paper from a feed board 26. Fromtheroll 25.the sensitized paper and the tracings are fed around thecylinderbetween the same and bands 23 until they pass over the top of thecylinder I! where the bands leave the cylinder and run forwardly andsubstantially horizontally to the bottom of a roll 27, upwardly at itsfront and rearwardly to a roll 28 at the rear part of the casing. At therear of roll 28,. the bands pass downwardly toa roll 29, forwardly fromthe bottom of the roll to the bottom of the roll3il, and from the sameupwardly to roll.24.

The heat generated bylamp [8, unless dissipated, would injure thesensitized paper and otherwise impair the printing operation In. ac-

cordance with this invention, the lamp andcylinder H are. cooled byproviding an exhaust outlet 3| in the back or rear wall 13, preferablyin the lower part of the casing, and an exhaust fan 32 to force airoutwardlythroughsaid outlet, I

thereby drawingin coolair through openings provided in the casing.

According to the present inventionysubstantially uniform cooling of thecylinder Il may be obtained, and this cooling is effected by means ofair flow induced by said fan 32. To this end, the cylinder ends are.spaced inwardly from the side walls It and IE to permit the flow of airaround such ends of thecylinder. IT, as indicated by the arrows inFigure 2. Beyondsaid cylinder ends are provided openings 33 and. 34covered by caps 35 and 35. Extending through the cylinder l1 and throughsuitable close-fitting openings in thecaps 35 and 36, is a duct.3'lwhich is open at both ends to receive the outside air.

The duct 37. is of substantial cross-section and preferably isshaped.insuch-a manner thatthe sideadjacent. the cylinder- H. is cylindrical,preferaby. having -a curvature above the; axis of the cylinder ll. Itwill be observed that the duct3T serves as a light shield to preventlight from reaching he portion .of the cylinderil'l where the tracingand print are not in contact. The narrow face of the duct, facingrearwardly with reference to the. rotationof the cylinder ip io-.chambers within the caps 35 and 36. Air is also .drawn. into the casingabove the feed board 26,

as indicated by the corresponding arrows on Figure 1, thus producing acooling effect at the initerior of the casing.

According to another feature of the invention,

.outside air is drawn into the casing above the cylinder ll through anopening 2| in the front of thecasing, as indicated by the correspondingarrows on Figure 1, and at this point, the vacuum chamber is utilized toseparate the tracings from the sensitized paper, thus eliminating theneed for a special device to effect such separation. To this end, thereis provided-a receiving tray 39 extending. across the front of thecasing and connected to theside walls thereof. Said tray 39 includes acurved bottom) and asubstantially horizontal portion over the bandsbetween the rolls '24 and 25. Astripping edge 22 is formed on the tray39 either tozengage the cylinder i'l yieldingly, or:to1.be.spacedslightly away therefrom.

Each tracing H with the sensitized paper beneath it is fed from the feedboard 26 over a horizontal stretch of bands 23 to the cylinder l1 andcarried around the cylinder l1 to the top thereof. There such sensitizedpaper is held against the lower sides of the bands 23 by the partialvacuum in the casing and fed forwardly beneath the bands, the tracingsbeing separated from the sensitized paper by gravity and air agitationand falling into the tray 39. After the exposed paper reaches roll 21,the bands continue in their movement and pass around the'roll 21 frombelow and. then rearwardly as hereinbefore described, the guide fingers4| assisting the printing paper around roll 42 on its way to a developerunit above said casing l0.

Since direct cooling of a mercury arc lamp reduces its efiiciency andlife, it will be seen that the present invention provides .a. highlyadvantageous structure in thatthe cooling air is di rected away from thelamp and about the inner surface of the cylinder. Directair currents arethus avoided around the. lamp which is thus maintained in an atmosphereof substantially free air.

With reference to thestructure shown in Fi ure 3, the casing. l4 isshownas being provided with caps 35 and 36 in which the duct 31 is mounted ina manner similar tothat shown in Figures. 1 andZ. In. the form shown inFigure 3, however, the casing 14. is formed withextensions '50 which,lie withinv the caps 35and 36 and which are. provided withcircularopenings 5| within which. the rotatable'cylinder H is received. Circulargaskets 52 serve to seal the space between the cylinder IT and the walls50. One or more openings 53 are formed in each wall 50 in order that theinterior of. the caps 35' and 35 may communicate with, the: interior ofthe casing l4 and provide the desired vacuum effect within the cylinderH. In this structure, it will be seen that the cooling air is drawn intothe ductfrom the outside of the machine, then, from the duct 31 throughthe apertures 38 and into the interior of the cylinder IT. The vacuumproduced by the fan 32 draws the air from the cylinder I1 into the endcaps 35 and 3t, and then through the openings 53 into the interior ofthe casing Hi.

In the form of the invention shown in Figures 4 and 5, a casing 60 isformed with end walls 6! which provide hollow chambers 62. Louvers 63permit air to be drawn within the chamber 62. The end walls 6| areformed with inner plates 64 within which a source of illumination 65 ismounted, and also within which a hollow duct 66 is mounted, the ends ofthe duct being open so they communicate with the interior of the endwalls 6|. As in the forms shown in Figures 1, 2, and 3, the duct isprovided with apertures here designated 61 which communicate with theinterior of an enclosing element 68. In the form shown in the drawings,the enclosing element is circular in cross-section and is provided witha transparent portion 69 over which the tracing and sensitized paper aremoved by means of endless belts !0 in a manner similar to that describedin connection with Figures 1, 2, and 3. A reflector and shield H areprovided so that the illuminating means 65 directs light only upon thetransparent portion 69.

In the form shown in Figures 4 and 5, the transparent portion 69 of theenclosing element 68 terminates short of the inner plates 64, so thatair drawn through the apertures 61 and into the enclosing element 68continues into the lower portion of the casing and is exhaustedtherefrom by means of a fan 12 which is similar in construction andoperation to the fan 32. The fan 12 discharges the air into a transversechamber 13 and then to the atmosphere, thus maintaining a partial vacuumwithin the entire casing 60 so that the interior of the enclosingelement 68 is subjected to the vacuum. In this fashion, the cooling airdrawn through the louvers 63 and into the ends of the tube 66 isdirected through the openings 61 into the enclosing element 68.

In view of the manner in which the duct 56 and openings 61 are mounted,the cOOling'air follows a generally helical path through the enclosingelement 63, as indicated by the arrows in Figures 4 and 5.

The enclosing element 68 is fixedly mounted within the casing so thatthe tracings and sensitized paper slide over the surface of thetransparent portion 69 and are discharged at the top of the enclosingelement 68 as will be apparent in Figure 5.

In order that the bands l0 may be cooled, air is also drawn into thecasing through an opening 14 at the rear of the casing. A V-shapedbafile plate 15 is provided so that the bands H! in the center of themachine receive more cooling air than the bands at the ends, thus toprovide uniform cooling of all of the bands and to correct the tendencyof the bands in the center portion of the machine from being heated to agreater extent than the bands at the ends thereof.

t should be understood that various changes may be made, and thatvarious features may be used without others, without departing from thetrue scope and spirit of the invention.

1. claim:

1. In a machine of the character specified, the combination with acylinder having at least a portion thereof light-transmitting andilluminating means therein, of means forproducinguniform 6. cooling ofthe cylinder throughout its length comprising air supply means disposedlongitudinally within said cylinder, said air supply means having atleast one end open to a source of cool air and having openingsintermediate the ends of the cylinder and along the length thereof tosupply cool air in proper proportion and in directions tending toproduce air currents along the inner surface of said cylinder, and meansoverlying at least one end of the cylinder for withdrawing heated airfrom the cylinder, thereby imparting axial components of motion to saidair currents and drawing cool air into and through said air supplymeans.

2. In a printing machine for sensitized paper, the combination with alight-transmitting cylinder and illuminating means therein, of coolingmeans for said cylinder comprising a duct in said cylinder havingopenings intermediate the ends of said cylinder and along the lengththereof to connect the interiors of said duct and cylinder, the interiorof said duct communicating with the outside air and the openings thereofbeing directed to produce currents of air along the internal surface ofthe cylinder, and means for drawing air from at least one end of thecylinder thereby drawing cool outside air into said duct and from saidduct into said cylinder.

3. In a printing machine for sensitized paper, the combination with alight-transmitting cylinder and illuminating means therein, of coolingmeans for said cylinder comprising a duct in said cylinder havingopenings intermediate the ends ofsaid cylinder and along the lengththereof to connect the interiors of said duct and said cylinder, theinterior of said duct communicating with the outside air and saidopenings being directed to produce whirling currents at the internalsurface of said cylinder, and means for drawing air from both ends ofthe cylinder and in connection with such whirling currents producinghelical currents of air, thereby drawing cool outside air into said ductand from said duct into said cylinder.

4. In a machine of the character specified, the combination with alight-transmitting rotary cylinder, illuminating means in said cylinderadjacent the axis thereof; of a casing about said cylinder with itssides spaced from the ends of the cylinder, means for exhausting airfrom the cylinder into the casing and from the casing to the atmosphere,and an air supply duct passing through the cylinder at one side of theillumininating means, said duct communicating with the outside air andhaving an aperture therein adjacent the inner wall of the cylinder andalong the length thereof between the ends of the cylinder to supply airto the interior thereof.

5. In a machine of the character specified, the combination with alight-transmitting rotary cylinder, illuminating means in said cylinderadjacent the axis thereof; of a casing about said cylinder with sidesspaced from the ends of the cylinder, means for exhausting air from thecylinder into the casing and from the casing to the atmosphere, and anair supply duct passing through the cylinder at one side of theilluminating means, and through the side walls of the casing, said ducthaving at least one open end and having apertures adjacent the innerwall of the cylinder and along the length thereof for the passage of airinto the cylinder.

PAUL B. STREICH.

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